Visual deficits and retinotoxicity caused by the naturally occurring anthelmintics, Embelia ribes and Hagenia abyssinica.

The naturally occurring anthelmintics, Embelia ribes (Enkoko) and Hagenia abyssinica (Kosso), have been reported to possibly cause optic atrophy among the Ethiopian population. In this study we found retinal pathology and defects in visual behavior in chicks treated with Enkoko, Kosso, or embelin, a crystalline extract of E. ribes.

The effect of eye enucleation on the number of fibres in the supraoptic decussation of posthatch chicks (Gallus gallus).

In this study of the young chick we examine the effects of unilateral or bilateral eye enucleation on the number of axons in the supraoptic decussation, a major interhemispheric tract subserving visual function. On posthatch day 25, chicks underwent removal of either one or both eyes. After a survival period of 32 days, electron microscopic examination of the supraoptic decussation revealed a substantial loss of fibres.

Molindone and hepatotoxicity.

An adolescent male with chronic schizophrenic disorder, paranoid type, was treated with molindone. He developed hepatotoxicity in the early treatment phase as evidenced by flu-like symptoms and laboratory abnormalities of liver functions. These symptoms and his hepatic functions improved on discontinuing molindone.

Successful treatment of maternal septicemia due to Listeria monocytogenes at 26 weeks' gestation.

A case of successful therapy with ampicillin of maternal septicemia due to Listeria monocytogenes at 26 weeks' gestation with resultant delivery at term of a normal neonate is reported. The ability to positively influence the outcome of hematogenously acquired maternal-fetal infection is stressed.

Visual deficits following intraocular treatment of chicks with glutamate or kainic acid.

After intraocular treatment with kainate or glutamate, chicks were tested for visual discrimination performance, pecking aim, bead detection, optokinetic response and pupillary response. Kainate at an amount of 6 nmol per eye impaired performance in all of the tests except pupillary response. No effects were seen after 0.

The effects of binocular and monocular occlusion on the number of optic nerve axons containing degenerative organelles.

In this study chicks were incubated in the dark and then reared for 2 days with either none, one or both eyes occluded. Cross-sections of the optic nerves were examined for profiles of axons containing accumulations of degenerative organelles. There were significantly more organelle-containing axons in the non-occluded and monocularly occluded birds compared with the binocularly occluded birds.

Sequential treatment with low doses of kainic acid alters sensitivity of retinal cell types.

Examination of chick retinae soon after treatment with a single intraocular injection of 5 nmol kainic acid revealed degenerative changes in a small population of neurons located in the outer aspect of the inner nuclear layer, consistent with either bipolar and/or horizontal cells. Damage to the outer plexiform layer was also present. After one week, affected retinae were clear of neuronal debris.

Sex-dependent structural asymmetry of the medial habenular nucleus of the chicken brain.

An investigation of structural asymmetry in the avian brain was conducted on the epithalamic medial habenular nucleus of the chicken. Twelve male and ten female two-day-old chickens were used for a morphometric evaluation of asymmetry. The medial habenular nucleus was measured from paraffin-wax-embedded, 8 micron-thick sections by use of a semiautomatic image analyser.

Myelogenesis and estimation of the number of axons in the anterior commissure of the chick (Gallus gallus).

By use of light- and electron microscopy the anterior commissure of the chick was studied at different times during development. Between the 19th day of incubation and the 35th day after hatching the cross-sectional area of the anterior commissure, as determined from mid-sagittal sections, undergoes a 6-fold increase in size. Thereafter the area remains fairly constant.

Evidence for self-absorption of terminals by developing axons of retinal ganglion cells in the chick.

The appearance of membrane-bound degenerative organelles in chick optic nerve axons was studied at the electron microscopic level. A semiquantitative analysis revealed a sharp increase in the number of axons containing accumulations of such organelles during the second day after hatching. In dark-reared chicks this increase was retarded, suggesting the presence of a light-influenced event in the early post-hatch period.

The course of axons of retinal ganglion cells within the optic nerve and tract of the chick (Gallus gallus).

Small laser lesions placed in the posthatch chicken retina resulted in axotomy and then death of all ganglion cells located in a sector peripheral to the primary damage. With the use of silver techniques, the patterns of degenerating retinal fibers in the optic nerve, chiasm, and optic tract were examined. In the proximal part of the optic nerve, radial retinal lesions resulted in a sheet of degenerating axons along the rostrocaudal extent of the nerve.

Topography of primary visual centres in the brain of the chick, Gallus gallus.

In a previous paper (Ehrlich and Mark, '83b) the primary visual centres of the chick were described. In this paper patterns of retinotopy are examined by means of silver degeneration and autoradiographic techniques following discrete laser lesions of the retina. Well-defined and complete retinotopic maps are found in each of the following visual centres: tectum, lateral anterior thalamus, lateroventral geniculate nucleus, superficial synencephalic nucleus, ectomammillary nucleus, and tectal grey.

An atlas of the primary visual projections in the brain of the chick Gallus gallus.

The localisation of the primary visual centres in the chick mesencephalon and diencephalon was determined by autoradiographic anterograde transport and degeneration techniques. Strong visual projections were found in the tectum, lateral anterior thalamic nucleus, lateroventral geniculate nucleus, superficial synencephalic nucleus, external nucleus, ectomammillary nucleus, tectal grey, dorsolateral anterior thalamus, rostrolateral part, and the pretectal optic area. Weaker retinal projections were found in the ventrolateral thalamus, two subregions of the dorsolateral anterior thalamus, lateral part, diffuse pretectal nucleus, dorsolateral anterior thalamus, magnocellular part, and the hypothalamus.

Composition of the supraoptic decussation of the chick (Gallus gallus). A possible factor limiting interhemispheric transfer of visual information.

In the chick the supraoptic decussation consists of dorsal, ventral, and subventral subregions. The dorsal region contains about 580000 axons of which 24% are myelinated. The mean diameters of unmyelinated and myelinated fibers are 0.

Retinotopy in the optic chiasm of chicks and its significance in an undesirable complication of lesioning the supraoptic decussation.

Following discrete lesions of the chick retina, the distribution of degenerating retinal ganglion cell axons in the optic chiasm was examined. A feature of particular interest was the dorsal aspect of the optic chiasm which was found to contain fibres originating from the superior temporal retina. The significance of this finding is discussed in relation to possible damage to the optic chiasm resulting as a consequence of sectioning the supraoptic decussation.

Asymmetry in the chicken forebrain during development and a possible involvement of the supraoptic decussation.

During the first week of post-hatch life, the chicken forebrain is asymmetrically susceptible to the action of cycloheximide. Between days 2 to 8 treatment of the left hemisphere, but not the right, causes long-lasting changes in behaviour. The right hemisphere is susceptible on days 10 and 11.

Reflectometric spectroscopy of adsorbed molecular layers.

A normal-incidence technique is described for obtaining IR absorption spectra of molecular layers adsorbed on a dielectric thin-film surface. In the experiment described, a low-power CO(2) laser beam is scanned across a molecular layer of 2-propanol adsorbed on a ZnSe film. Spectra for 1-5 monolayer coverages are compared with the liquid spectrum of the adsorbate.

Laser-induced defects of retinal development in chick embryos.

Retinae of 8-day-old chick embryos were exposed to laser beam irradiation and examined after hatching. The most prominent feature in the irradiated area was the presence of rosettes consisting of photoreceptors surrounded by an orderly arrangement of outer plexiform layer, inner nuclear layer and inner plexiform layer. The histological character of these rosettes raises questions of regeneration of retinal cells that have apparently withdrawn from the mitotic cycle and also the possibility of the regeneration of ganglion cell axons.

Composition of the tectal and posterior commissures of the chick (Gallus domesticus).

In chick, the tectal and posterior commissures form a continuous band of axons lying in the dorsal aspect of the meso-diencephalon. In midline sagittal sections, two zones can be clearly defined. The rostral zone (RZ) contains about 290,000 axons of which 32% are myelinated.

Deep-ultraviolet spatial-period division using an excimer laser.

We have used the deep-UV output from an ArF laser and a grating mask with 199-nm spatial period to fabricate a 99.5-nm-period grating pattern in polymethyl methacrylate resist by spatial-period division. For sub 100 nm, lithography of periodic and quasi-periodic patterns (including Fresnel zone plates) by spatial-period division, deep-UV radiation offers a number of advantages over soft x rays.

Optically induced microstructures in laser-photodeposited metal films.

Regular 0.15- to 0.5-microm-period ripple structures have been seen in laser-photodeposited Cd and Zn films.

Optical reflectance technique for observations of submonolayer adsorbed films.

An optical technique is described for detecting and measuring thicknesses of adsorbed films with subangstrom sensitivity. The technique relies on optical interference from an antireflecting thin-film structure that is predeposited on a transparent cell window: the reflectivity of the window depends linearly on the thickness of the molecular layer adsorbed from the gas in the cell.

Regional specialization of the chick retina as revealed by the size and density of neurons in the ganglion cell layer.

On the basis of both morphological criteria and survival after ganglion cell axotomy, three populations of cells can be recognized in the ganglion cell layer of the chick retina. These are: 1) Irregularly shaped cells, which are not affected by axotomy and lack Nissl stain. They comprise about 5% of the total cell population and are probably glial cells.